The mass of potassium hydroxide required to make 300.ocm3 of 0.4 moldm-3 solution is {KOH...

Chemistry

WAEC 2016

The mass of potassium hydroxide required to make 300.ocm³ of 0.4 moldm^-3 solution is {KOH = 56.0}

A. 26.88g
B. 13.44g
C. 6.72g
D. 3.36g

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Correct Answer: Option C

Explanation

300cm³ of 0.4moldm³

1000cm³ contains 0.4mole

300cm³ will contain \(\frac{300 \times 0.4}{1000}\)

= 0.12mole

Number of moles = \(\frac{Mass}{\text {Molecular mass}}\)

Mass = number of moles x m.mass

= 0.12 x 56 = 6.72g

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The mass of potassium hydroxide required to make 300.ocm3 of 0.4 moldm-3 solution is {KOH...

Correct Answer: Option C

Explanation

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